LONDONDERRY, Northern Ireland - Police in Northern Ireland have warned of "an increased terrorist threat" and stepped up security against separatist republicans, the BBC said Wednesday.

Without giving details, the Police Service of Northern Ireland said intelligence received last week indicated Irish Republican Army fighters were preparing for a series of firebomb attacks. Since then, new information came in, prompting the escalation of the threat level, the report said.

Police issued a public warning, telling citizens to expect such things as street and highway vehicle checkpoints, and asking for patience and cooperation in reporting suspicious activity.

Chief Constable Hugh Orde said attacks elsewhere in Britain by the group called Real IRA were also possible.

"They have the intent to cause as much damage as they can to the peace process in Northern Ireland," he told reporters.

Such a public alert hasn't been issued in several years, the BBC said.